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  • B01J29/00—Catalysts comprising molecular sieves
  • B01J29/82—Phosphates
  • B01J29/84—Aluminophosphates containing other elements, e.g. metals, boron
  • B01J29/85—Silicoaluminophosphates [SAPO compounds]
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  • B01D53/34—Chemical or biological purification of waste gases
  • B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
  • B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
  • B01D53/9404—Removing only nitrogen compounds
  • B01D53/9409—Nitrogen oxides
  • B01D53/9413—Processes characterised by a specific catalyst
  • B01D53/9418—Processes characterised by a specific catalyst for removing nitrogen oxides by selective catalytic reduction [SCR] using a reducing agent in a lean exhaust gas
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  • B01J35/56—Foraminous structures having flow-through passages or channels, e.g. grids or three-dimensional monoliths
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  • B01J37/02—Impregnation, coating or precipitation
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  • B01J37/30—Ion-exchange
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  • C01B37/00—Compounds having molecular sieve properties but not having base-exchange properties
  • C01B37/06—Aluminophosphates containing other elements, e.g. metals, boron
  • C01B37/08—Silicoaluminophosphates [SAPO compounds], e.g. CoSAPO
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  • C01B39/00—Compounds having molecular sieve and base-exchange properties, e.g. crystalline zeolites; Their preparation; After-treatment, e.g. ion-exchange or dealumination
  • C01B39/54—Phosphates, e.g. APO or SAPO compounds
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  • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
  • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
  • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
  • F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
  • F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion
  • F01N3/206—Adding periodically or continuously substances to exhaust gases for promoting purification, e.g. catalytic material in liquid form, NOx reducing agents
  • F01N3/2066—Selective catalytic reduction [SCR]
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  • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
  • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
  • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
  • F01N3/24—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by constructional aspects of converting apparatus
  • F01N3/28—Construction of catalytic reactors
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  • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
  • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
  • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
  • F01N3/24—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by constructional aspects of converting apparatus
  • F01N3/28—Construction of catalytic reactors
  • F01N3/2803—Construction of catalytic reactors characterised by structure, by material or by manufacturing of catalyst support
  • F01N3/2825—Ceramics
  • F01N3/2828—Ceramic multi-channel monoliths, e.g. honeycombs
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  • B01D—SEPARATION
  • B01D2251/00—Reactants
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  • B01D2251/202—Hydrogen
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  • B01D2251/00—Reactants
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  • B01D2251/206—Ammonium compounds
• • B—PERFORMING OPERATIONS; TRANSPORTING
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  • B01D2251/00—Reactants
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  • B01D2251/206—Ammonium compounds
  • B01D2251/2065—Ammonium hydroxide
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  • B01J2229/00—Aspects of molecular sieve catalysts not covered by B01J29/00
  • B01J2229/10—After treatment, characterised by the effect to be obtained
  • B01J2229/18—After treatment, characterised by the effect to be obtained to introduce other elements into or onto the molecular sieve itself
  • B01J2229/186—After treatment, characterised by the effect to be obtained to introduce other elements into or onto the molecular sieve itself not in framework positions
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  • C01P2002/72—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data by d-values or two theta-values, e.g. as X-ray diagram
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  • F01N2330/00—Structure of catalyst support or particle filter
  • F01N2330/06—Ceramic, e.g. monoliths
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  • F01N2370/00—Selection of materials for exhaust purification
  • F01N2370/02—Selection of materials for exhaust purification used in catalytic reactors
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  • F01N2510/00—Surface coverings
  • F01N2510/06—Surface coverings for exhaust purification, e.g. catalytic reaction
  • F01N2510/063—Surface coverings for exhaust purification, e.g. catalytic reaction zeolites
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  • F01N2610/00—Adding substances to exhaust gases
  • F01N2610/02—Adding substances to exhaust gases the substance being ammonia or urea
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  • F01N2610/00—Adding substances to exhaust gases
  • F01N2610/04—Adding substances to exhaust gases the substance being hydrogen
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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  • Y02T10/00—Road transport of goods or passengers
  • Y02T10/10—Internal combustion engine [ICE] based vehicles
  • Y02T10/12—Improving ICE efficiencies

Definitions

• the subject of the invention is a process for the preparation of a zeolite silicoaluminophosphate (SAPO) material of AFX structure, as well as the use of this material, in particular for the selective catalytic reduction of NOx in the presence of a reducing agent. especially on diesel or spark ignition engines.
• SAPO zeolite silicoaluminophosphate
• the zeolites exchanged with transition metals are used as catalysts for selective catalytic reduction to ammonia applications, designated by the acronym "SCR” for "Selective Catalytic Reduction” (NH3-SCR), in transport .
• Small-pore zeolites particularly copper-exchanged chabazites, are particularly suitable. They exist commercially in the form of silico-aluminophosphate Cu-SAPO-34, alumino-silicic Cu-SSZ-13 (or Cu-SSZ-62). Their hydrothermal behavior and NOx conversion efficiency, especially at low temperatures, make them the current references.
• the use of zeolites AFX structural type for NH3-SCR applications is known, but few studies evaluate the effectiveness of catalysts implementing this zeolite.
• US2016 / 0137518 discloses the synthesis of a quasi-pure transition metal zeolite AFX and its use for NH3-SCR applications. No particular form of AFX zeolite is mentioned, however the materials formed are silica-alumina and non-silico-aluminophosphates.
• JP 2014-148441 describes the synthesis of an AFX zeolite, in particular an SAPO-56 comprising copper which can be used for the reduction of NO x .
• the AFX zeolite is synthesized and then added to a mixture comprising an alcohol and a copper salt, the whole being calcined.
• the copper is therefore added once the structural type SAPO zeolite AFX formed. This zeolite appears to have increased resistance to the presence of water.
• WO 2017/080722 discloses a direct synthesis of a zeolite comprising copper. This synthesis requires starting from a zeolite of structural type FAU and using a complexing agent TEPA and an element M (OH) x to result in different types of zeolites, mainly of type CHA. Zeolites of the ANA, ABW, PHI and GME type are also produced.
• the Applicant has discovered a process for the direct synthesis of a SAPO material comprising AFX structural type copper, exhibiting interesting performances for the conversion of NOx, in particular higher than those obtained with SAPO zeolites of the AFX structural type exchanged with copper.
• An advantage of the process according to the invention is to obtain, by means of a set of specific operating conditions, a SAPO material of pure AFX structural type, that is to say without any other crystalline or amorphous phase being observed. by X-ray diffraction (XRD).
• the direct synthesis method according to the invention makes it possible to obtain an SAPO material of structural AFX type comprising copper having improved properties compared to the catalysts of the prior art while simplifying the conventional synthesis.
• the use of the catalyst prepared according to the invention makes it possible to obtain a better conversion in the NOx conversion reaction by decreasing the amount of NO2 produced.
• the invention relates to a process for the preparation of an SAPO material of structural type AFX containing copper and comprising at least the following steps:
• the preparation process according to the invention comprises a step a) of mixing, in an aqueous medium, at least one source of aluminum, at least one source of silicon, from minus a source of copper, at least one source of phosphorus, a complexing agent TETA and a structuring agent TMHD to obtain a gel of formula:
• a / c is between 0.2 and 0.9, more preferably between 0.4 and 0.8.
• b / c is 0.4 and 0.9, more preferably 0.6 to 0.8.
• g / c is between 10 and 70, more preferably between 30 and 50.
• d / c is between 1 and 2.5.
• e / c is between 0.01 and 0.09, more preferably 0.02 to 0.08.
• the source of aluminum may be any source of aluminum known to those skilled in the art.
• the aluminum source is preferably sodium aluminate or an aluminum salt, for example chloride, nitrate, hydroxide or sulphate, an aluminum alkoxide or alumina as such, preferably in hydrated or hydratable form, such as, for example, colloidal alumina, pseudo-boehmite, gamma-alumina or alpha or beta trihydrate, an aluminosilicone zeolite such as USY (Ultrastable Y, structural type FAU). It is also possible to use mixtures of the sources mentioned above.
• the silicon source may be any source of silicon known to those skilled in the art.
• the silicon source is preferably powdered silica, silicic acid, colloidal silica, dissolved silica or tetraethoxysilane (TEOS) or an aluminosilicone zeolite such as for example USY (Ultrastable Y, structural type FAU).
• TEOS tetraethoxysilane
• aluminosilicone zeolite such as for example USY (Ultrastable Y, structural type FAU).
• the powdered silicas it is possible to use precipitated silicas, especially those obtained by precipitation from an alkali metal silicate solution, pyrogenic silicas, for example "CAB-O-SIL" and silica gels.
• colloidal silicas having different particle sizes for example having a mean equivalent diameter of between 10 and 15 nm or between 40 and 50 nm, such as those sold under registered trademarks such as "LUDOX", may be used.
• the silicon source is CAB-O-SIL M5.
• the copper source is at least one species capable of releasing copper in solution in reactive form, for example sulphates, nitrates, chlorides, oxalates, organometallic copper complexes, but also mixtures of the sources mentioned above.
• the copper source is chosen from sulphates and nitrates.
• the phosphorus source may be chosen from phosphorus-based acids such as, for example, phosphoric acid or phosphorous acid, and organic phosphates, for example triethylphosphate.
• the phosphorus source may also be an aluminophosphate.
• the source of phosphorus is phosphoric acid
• the structuring agent is N, N, N ', N' tetramethyl hexane-1,6 diamine (TMHD). This structuring agent makes it possible to obtain an SAPO material of structural AFX type.
• the complexing agent used in step a) of the process according to the invention is triethylenetetramine (TETA).
• TETA triethylenetetramine
• the Applicant has discovered that the specific use of TETA in combination with the other parameters of the process according to the invention, in particular a low shear rate, of less than 50 s 1 , made it possible to obtain an SAPO material of structural AFX type comprising copper without the presence of other crystalline or amorphous phases observable by XRD, further having improved properties compared to a material prepared by other methods of synthesis.
• the mixture of step a) is advantageously cold-formed, at least for the addition of the source of aluminum and / or phosphorus so as to limit the temperature rise due to the dilution exotherm and allow homogeneous dissolution of the constituents.
• the addition of the source of aluminum and / or phosphorus is carried out in an ice-water bath or any equipment allowing heat evacuation in an equivalent manner and adapted to the volume of the mixture produced.
• the preparation process according to the invention comprises a hydrothermal treatment step b) of said gel at a temperature of between 170 and 220 ° C., under autogenous reaction pressure, for a period of between 1 and 3 days with a lower shear rate. at 50 s 1 to obtain the crystallization of said structural SAPO material AFX structural material comprising copper.
• step b) of the process according to the invention the gel obtained at the end of step a) of mixing is subjected to a hydrothermal treatment, carried out at a temperature of between 170 and 220 ° C., preferably between 190 and 210 ° C, under autogenous reaction pressure, for a period of between 1 and 3 days, preferably between 1 and 2 days, to obtain the crystallization of said structural SAPO zeolite AFX.
• the solid obtained is filtered, washed and then dried to obtain said SAPO zeolite AFX structural type in powder form.
• Step b) of the preparation process according to the invention is carried out with a shear rate of less than 50 s 1 , therefore between 0 and 50 s 1 .
• a shear rate of 0 s 1 corresponds to a static mode, that is to say in the absence of agitation.
• step b) of the preparation process according to the invention is carried out in static mode.
• step b) of the preparation process according to the invention is carried out with a shear rate of between 0.1 and 50 s 1 , for example with an Archimedean screw.
• the Applicant has in fact discovered that the use of a static mode or with a very low shear in combination with the other parameters of the process according to the invention, in particular the use of a complexing agent TETA, made it possible to obtain an SAPO material of structural AFX type comprising copper without presence of other crystalline or amorphous phases observable by XRD, which furthermore has improved properties with respect to a material prepared by other synthetic methods.
• the SAPO structural type material AFX comprising copper without the presence of other crystalline or amorphous phases observable by XRD is obtained. Its X-ray diffractogram corresponds to International Center for Diffraction Data (ICDD) number: 04-013-1370.
• the preparation process according to the invention advantageously comprises a step c) of heat treatment carried out after step b) comprising a treatment under dry inert gas, advantageously nitrogen, at a temperature between 400 and 600 ° C, preferably between 500 and 600 ° C for a period of between 5 and 15 h, preferably between 6 and 10 h, followed by treatment by combustion in dry air, at a temperature between 400 and 600 ° C, preferentially between 500 and 600 ° C for a period of between 5 and 15 h, preferably between 6 and 10 h, the dry air flow rate being preferably between 0.5 and 1.5 l / h / g of solid to treat, preferably between 0.7 and 1.2 l / g / h.
• a treatment under dry inert gas advantageously nitrogen
• the first treatment under inert gas allows in particular a thermo-cracking of the organic molecules before releasing the porosity during the combustion treatment.
• said treatment under inert gas makes it possible to maintain the integrity of the structure of the material prepared by the process according to the invention during the combustion treatment.
• the material prepared according to the invention can be used as catalyst, adsorbent, catalyst support or any other application known to those skilled in the art for an SAPO material of AFX structural type comprising copper.
• the material obtained is in the form of a light blue powder whose intensity depends on the quantity of copper contained and its X-ray diffractogram corresponds to an SAPO of structural type AFX, as defined by the International Zeolite Association (IZA ).
• the amount of copper contained in said material can vary from 0.5 to 8% by weight of the total mass of the material in its anhydrous form.
• the preparation process according to the invention advantageously comprises, at the end of step b) of the process according to the invention, or of step c) of the process according to the invention if it is implemented, a step ion exchange comprising contacting the solid obtained at the end of step b), advantageously at the end of step c), with a solution comprising a species capable of releasing copper in solution in the form of reactive, preferably selected from sulfates, nitrates, chlorides, oxalates, organometallic copper complexes and mixtures thereof, stirring at room temperature for a period of between 1 h and 2 d, preferably for a period of between 0.5 and 1 5 j, the concentration of said species able to release the copper in said solution being a function of the amount of copper that is to be incorporated in said solid.
• a species capable of releasing copper in solution in the form of reactive preferably selected from sulfates, nitrates, chlorides, oxalates, organometallic copper complexe
• the amount of copper contained in said solid is ultimately between 0.5 to 8% by weight relative to the total mass of the solid in its anhydrous form.
• the applicant has discovered that the material obtained by the process according to the invention has characteristics different from the structural SAPO materials of the AFX structural type comprising copper known hitherto. In particular, the material obtained by the process according to the invention has improved properties for the conversion of NO x .
• the invention therefore also relates to an SAPO structural type AFX materials comprising copper obtained by the method according to the invention, comprising at least the following steps:
• a / c being between 0.1 and 1
• b / c being between 0.1 and 1
• g / c being between 1 and 100
• dc being between 0.5 and 4
• e / c being between 0.005 and 0.1
• f / e being between 1 and 1.5;
• the material prepared according to the invention has an AFX structure according to the classification of the International Zeolite Association (IZA). This structure is characterized by X-ray diffraction (XRD).
• IZA International Zeolite Association
• XRD X-ray diffraction
• the measurement error A (dhki) on dhki is calculated by means of the Bragg relation as a function of the absolute error ⁇ (2 ⁇ ) assigned to the measurement of 2 ⁇ . An absolute error ⁇ (2 ⁇ ) equal to ⁇ 0.02 ° is commonly accepted.
• the relative intensity I re i assigned to each dhki value is measured from the height of the corresponding diffraction peak. Comparison of the diffractogram with the International Center for Diffraction Data (ICDD) databases using software such as DIFFRACT. SUITE also allows us to identify the crystalline phases present in the material obtained.
• ICDD International Center for Dif
• the qualitative and quantitative analysis of the chemical species present in the materials obtained is made by X-ray fluorescence spectrometry (FX).
• FX X-ray fluorescence spectrometry
• This is a technique of chemical analysis using a physical property of matter, the fluorescence of X-rays.
• the spectrum of X-rays emitted by the material is characteristic of the composition of the sample, by analyzing this spectrum, one can deduce the elemental composition, that is to say the mass concentrations in elements.
• the loss on ignition of a sample is calculated as the mass difference of the sample before and after calcination at 550 ° C for 2 h. It is expressed in% corresponding to the percentage of loss of mass.
• the invention also relates to the use of the material prepared by the process according to the invention, advantageously shaped by deposition in the form of a coating ("washcoat" according to the English terminology) on a honeycomb structure, filtering or no, for the selective reduction of NO x by a reducing agent such as NH3 or H2.
• Said honeycomb structure thus coated constitutes a catalytic bread.
• Said structure may be composed of cordierite, silicon carbide (SiC), aluminum titanate (AITi) or any other material whose porosity is between 30 and 70%.
• the quantity of material prepared by the process according to the invention deposited on said structure is between 40 to 140 g / l for the filtering structures and between 120 and 200 g / l for structures with open channels.
• the actual coating comprises SAPO structural type material AFX comprising copper prepared according to the invention, advantageously associated with a binder such as cerine, zirconium oxide, alumina, silica-alumina non-zeolitic, titanium oxide, a mixed oxide of the cerine-zirconia type, a tungsten oxide.
• Said coating is advantageously a solution or a suspension. It is applied to said structure in any manner known to those skilled in the art. Said structure may be coated with one or more layers.
• the coating comprising the SAPO structural type material AFX comprising copper prepared according to the invention is advantageously associated with, that is to say covers one or is covered by, another coating having NOx reducing or promoting capabilities. oxidation of pollutants, in particular that of ammonia.
• Said structure coated with the material prepared by the process according to the invention is advantageously integrated in an exhaust line of an internal combustion engine operating mainly in lean mixture, that is to say in excess of air relative to to the stoichiometry of the combustion reaction as is the case for diesel engines for example.
• the exhaust gases contain the following pollutants: soot, unburned hydrocarbons (HC), carbon monoxide (CO), nitrogen oxides (NOx).
• HC unburned hydrocarbons
• CO carbon monoxide
• NOx nitrogen oxides
• Upstream of said structure can be placed an oxidation catalyst whose function is to oxidize HC and CO and a filter for removing soot from the exhaust gas, the function of said structure being to eliminate NOx, its operating range being between 100 and 900 ° C and preferably between 200 ° C and 500 ° C.
• FIG. 1 shows an image obtained by scanning electron microscopy (SEM) of the Cu-SAPO material of structural AFX type obtained by the process according to the invention.
• FIG. 2 shows the NOx conversion results, the Ex 1, Ex 4, Ex 7 and Ex 8 curves respectively corresponding to the tests carried out with the materials prepared according to Example 1, Example 4, Example 7 and EXAMPLE 8 At abscissa 400 ° C., the curves correspond, respectively, from bottom to top to Ex 1, Ex 8, Ex 4 and Ex 7.
• FIG. 3 shows an X-ray diffractogram of the Cu-SAPO material obtained according to Example 7.
• an SAPO-56 zeolite exchanged with Cu is synthesized according to the prior art.
• the copper is introduced by ion exchange.
• 131.33 g of phosphoric acid and 62.30 g of alumina are cold mixed in 213.80 g of water. This mixture is kept in an ice-water bath and dispersed with vigorous stirring. The mixture is made up with 125.80 g of deionized water with stirring until homogenization. 20.39 g of fumed silica, then 197.17 g of TMHD structurant are added with vigorous stirring at room temperature until homogenization of the suspension.
• the reaction mixture has the following molar composition: 0.6 S102: 0.8 Al2O3 1.0 P2O5: 2 TMHD: 40 H2O Hydrothermal treatment stage
• the gel obtained is left in an autoclave at a temperature of 200 ° C. for 4 days without stirring.
• the crystals obtained are separated and washed with deionized water until a pH of the washings of less than 8 is obtained.
• the washed material is dried.
• a DRX analysis shows that the product obtained is a SAPO-56 zeolite of synthetic and pure raw AFX structural type (ICDD sheet, PDF 04-03-1370).
• the synthetic SAPO-56 zeolite is treated under a stream of dry N 2 at 550 ° C. for 8 h and then calcined under a stream of dry air at 550 ° C. for 8 h.
• the loss on ignition (PAF) is 21% by weight.
• the calcined SAPO-56 zeolite is brought into contact with a solution of [Cu (NH 3) 4] (NO 3) 2 for 1 day with stirring at room temperature. The final solid is separated, washed and dried.
• a DRX analysis shows that the product obtained is a SAPO-56 zeolite of synthetic and pure raw AFX structural type (ICDD sheet, PDF 04-03-1370).
• the reaction mixture has the following molar composition: 0.6 S1O2: 0.8 Al2O3: 1.0 P2O5: 2 TMHD: 0.06 CuS0 4 : 0.06 TEPA: 40 H2O
• the gel obtained is separated into 4 samples left in an autoclave at a temperature of 200 ° C. for 1, 2, 3 and 4 days, respectively, with stirring, with a shear rate of 40 s 1 .
• the crystals obtained are separated and washed with deionized water until a pH of the washings of less than 8 is obtained.
• the washed material is dried.
• the XRD analyzes show that the product obtained after 1, 2, 3 and 4 days of autoclaving is a SAPO-56 zeolite (ICDD sheet, PDF 04-03-1370) at about 85% by weight, mixed with the SAPO-zeolite. 34 (ICDD sheet, PDF 00-047-0429) at about 15% by weight.
• the gel obtained is left in an autoclave at a temperature of 200 ° C. for 4 days under stirring with a high shear (greater than 1000 s 1 ).
• the crystals obtained are separated and washed with deionized water until a pH of the washings of less than 8 is obtained.
• the washed material is dried.
• An XRD analysis indicates the presence of a mixture of SAPO-17 (ICDD file, PDF 00-047-0621) and SAPO-34 (ICDD file, PDF 00-047-0429). It is observed that SAPO-56 is not obtained under these synthesis conditions.
• Example 4 (compliant)
• a SAPO-56 zeolite with direct incorporation of Cu is synthesized using a complexing agent Triethylenetetramine (TETA) and crystallization under low shear.
• TETA Triethylenetetramine
• the reaction mixture has the following molar composition: 0.6 S1O2: 0.8 Al2O3: 1.0 P2O5: 2 TMHD: 0.06 CuS0 4 : 0.06 TETA: 40 H2O
• the gel obtained is separated into 2 samples left in an autoclave at a temperature of 200 ° C. for 1 and 2 days, respectively, with stirring, with a shear rate of 40 s 1 .
• the crystals obtained are separated and washed with deionized water until a pH of the washings of less than 8 is obtained.
• the washed material is dried.
• a X-ray analysis shows that the product obtained is pure Cu-SAPO-56 zeolite (sheet ICDD, PDF 04-03-1370) of structural AFX type, that the hydrothermal treatment stage lasted one or two days.
• Heat treatment step
• a sample is treated under a stream of dry N2 at 550 ° C for 8 h, and then calcined under a stream of dry air at 550 ° C for 8 h.
• a XRD analysis shows that the product obtained is a pure zeolite AFX structural type.
• FX X-ray fluorescence chemical analysis
• the mixing step is carried out in the same manner as in Example 4.
• the gel obtained is left in an autoclave at a temperature of 200 ° C. for 3 days under stirring with high shear (shear rate greater than 1000 sec -1 ).
• the crystals obtained are separated and washed with deionized water until a pH of the washings of less than 8 is obtained.
• the washed material is dried.
• the gel obtained is left in an autoclave at a temperature of 200 ° C. for 1 day with stirring with high shear (shear rate greater than 1000 sec -1 ).
• the crystals obtained are separated and washed with deionized water until a pH of the washings of less than 8 is obtained.
• the washed material is dried.
• a DRX analysis shows that the product obtained with high shear crystallization is a mixture of SAPO-56 zeolites (ICDD record, PDF 04-03-1370) and SAPO-17 (ICDD record, PDF 00-047-0621).
• This example differs from Example 4 by a different composition of the gel obtained at the end of the mixing step. Mixing step
• the reaction mixture has the following molar composition: 0.8 S1O2: 0.8 Al2O3: 1.0 P2O5: 2 TMHD: 0.08 CuS0 4 : 0.08 TETA: 40 H2O
• the gel obtained is separated into several samples left in an autoclave at a temperature of 200 ° C. for a period of 1 to 2 days while stirring with a low shear (shear rate of 40 s 1 ).
• the crystals obtained are separated and washed with deionized water until a pH of the washings of less than 8 is obtained.
• the washed material is dried.
• a X-ray analysis shows that the product obtained is pure Cu-SAPO-56 zeolite (ICDD sheet, PDF 00-047-0621), for all the durations of the hydrothermal treatment step of between one and two days.
• a sample is treated under a stream of dry N2 at 550 ° C for 8 h, and then calcined under a stream of dry air at 550 ° C for 8 h.
• a XRD analysis shows that the product obtained is a pure zeolite AFX structural type.
• This example differs from Example 4 by a different composition of the gel obtained at the end of the mixing step.
• the reaction mixture has the following molar composition: 0.4 S1O2: 0.8 Al2O3: 1.0 P2O5: 2 TMHD: 0.04 CuS0 4 : 0.04 TETA: 40 H2O
• the gel obtained is separated into several samples left in an autoclave at a temperature of 200 ° C. for a period of 1 to 2 days while stirring with a low shear (shear rate of 40 s 1 ).
• the crystals obtained are separated and washed with deionized water until a wash water pH of less than 8 is obtained.
• the washed material is dried.
• a X-ray analysis shows that the product obtained is pure Cu-SAPO-56 zeolite (ICDD sheet, PDF 00-047-0621), for all the durations of the hydrothermal treatment step of between one and two days.
• a sample is treated under a stream of dry N2 at 550 ° C for 8 h, and then calcined under a stream of dry air at 550 ° C for 8 h.
• a XRD analysis shows that the product obtained is a pure zeolite AFX structural type.
• the X-ray fluorescence chemical analysis (FX) gave a Si / Al and Cu / Al ratio of 0.17 and 0.08, respectively.
• a XRD analysis shows that the product obtained is a pure zeolite AFX structural type.
• FX X-ray fluorescence chemical analysis
• a SAPO-56 zeolite with direct incorporation of Cu is synthesized using a complexing agent Triethylenetetramine (TETA) and crystallization under low shear. An additional amount of Cu is introduced by ion exchange. Mixing step
• a X-ray analysis shows that the product obtained is a pure SAPO-56 zeolite (ICDD sheet, PDF 00-047-0621) of structural AFX type, that the hydrothermal treatment stage lasted one or two days.
• a sample is treated under a stream of dry N2 at 550 ° C for 8 h, and then calcined under a stream of dry air at 550 ° C for 8 h.
• the calcined Cu-SAPO-56 zeolite obtained in this example is brought into contact with a solution of [Cu (NH 3) 4] (NO 3) 2 for 1 day with stirring at room temperature. The final solid is separated and dried.
• a DRX analysis shows that the product obtained is a pure SAPO-56 zeolite (ICDD sheet, PDF 00-047-0621).
• This charge has the following molar composition:

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